Our look at some of the big stories today in mobile: Google’s Android in-app payments service gets some early users — and maybe some confusion; Gartner says tablets drive up worldwide IT spend; and Hutchison’s Three posts a profit.

The earliest adopters of the service? Games developers, with a touch of publishing in the mix. Among them: PapayaMobile, which operates a social gaming network, has integrated the service into its Android platform so that its 10 million users (which it calls its Papayans) can make microtransactions while playing. Other games adopters include Glu Mobile (NSDQ: GLUU), which has added IAP into three games so far — Gun Bros, Deer Hunter Challenge and World Series of Poker Hold’em Legend — and Disney’s Tap Tap Revenge.

One publisher is also joining Android’s in-app billing fray: Comics from ComiXology, which will use the service to enable users to purchase individual comics.

Interestingly, one of the highest-profile games developers, Finland-based Angry Birds maker Rovio, which has made a lot of inroads into ways to monetise its mobile games, has not been one of the first to pick up the service.

One possible point of confusion (and possibly complaint): a developer that uses the Android in-app billing API will share the revenue on a 30/70 split, the same as a paid app in the Market. Meanwhile, Google’s One Pass service, announced by Eric Schmidt in Germany in February, is aimed specifically at publishers and appears to work on a much more favorable 10/90 share.

— Tablets: The still-young tablet market seems to already be making an impact on wider IT spending.

According to figures released today from Gartner, tablet spend worldwide will total $29.4 billion in 2011, a massive jump compared to $9.6 billion in 2010. That is projected to grow an average of 52 percent annually until 2015. In 2011, IT spending globally will total $3.6 trillion, a 5.6 per cent increase from $3.4 trillion in 2010.

This will be the first year that tablets will get included in the computing hardware category, and they will contribute two percent to Gartner’s projection of 9.5 percent growth in that segment.

— Three: The Hutchison Whampoa-owned mobile operator Three has posted a full-year profit for the first time in its eight-year history. Hutchison noted in its earnings reported yesterday that the Three group achieved a positive EBIT (earnings before interest and tax) of HK$2,931 million ($376 million), a growth of 133 percent compared to the same period a year ago. Taking all operations (Australia, Austria, Ireland, Italy, Sweden/Denmark, UK and Hong Kong/Macau) Three now has 29.7 million users.